High-energy electrical trauma remains a major cause of occupational injury and disability. Nonetheless, major advances in therapy have been slow to develop because of the unresolved questions regarding its pathophysiology. We have shown in laboratory studies that the biophysical mechanisms of tissue injury are more complex than previously thought, that is, both thermal and direct electrical mechanisms are likely to be involved, and their relative contribution is highly dependent on the duration of electrical current passage. Skeletal muscle and nerve cells are the most vulnerable to direct electrical mechanisms of cellular membrane damage (electroporation and electroconformational protein denaturation). Our subsequent reports indicate that it may by possible to restore viability to tissues injured by direct electrical mechanisms using biocompatible surfactants, whereas thermally injured (burned) tissue requires surgical excision. One essential need addressed in this project is to determine the relative contribution of thermal versus electrical mechanisms of tissue injury over a range of exposures characteristic of occupational electrical trauma. The proposed project would accomplish this by separately exposing tissue to the equivalent thermal and electrical stresses involved in a 60 Hz electrical trauma. A second essential need is to develop an imaging method for electrical injury diagnosis. We propose to refine magnetic resonance imaging (MRI) analysis sequences, useable on common hospital MRI machines, which can distinguish heat-damaged from pure electrical-damaged tissue on the basis of extent of tissue protein denaturation. Such a diagnostic tool would be of tremendous clinical value because rapid detection, discrimination and localization of tissue injury would accelerate and guide clinical management. Although essential for optimal electrical injury management, these methods would also be of practical clinical value for assessment of new medical therapies as well as valuable for pure thermal (hot and cold) injury evaluation.